Where does the spent shell casing exit the weapon?

The spent shell casing exits the weapon through the ejection port. In a firearm, the ejection port is a specialized opening that allows the spent casing from a fired round to be expelled from the chamber after the firing sequence. This is a critical part of the cycling process in semi-automatic or automatic firearms, as it ensures that the spent casing does not obstruct the chamber for the next round.

In contrast, the magazine is designed to hold ammunition, the chamber is where the cartridge is seated and fired, and the slide is a part of the action that moves to chamber a round and eject the spent casing, but it does not serve as the exit point for the spent casing. Therefore, the ejection port is uniquely identified for this specific function in firearm operation.